Food products, pharmaceuticals, etc. need inspection for contaminants. In the process of manufacturing these products, for example, contaminants such as metal fragments may get mixed in the products. In order to ensure the safety of the products, it is necessary to eliminate metallic contaminants from them and hence essential to detect the metallic contaminants.
Stainless steel is excellent in corrosion resistance and widely used in various products, mainly in the fields of kitchen utensils, building materials, domestic electrical equipment, automotive parts, dairy and fermentation tanks, chemical equipment, thermal insulating apparatus, etc. There are many stainless-steel products particularly in the field of food products, such as food product containers, and structural components, containers and so forth of all machines in food product manufacturing lines and food product manufacturing machines. It is impossible to avoid wear particles or fragments of such stainless steel products getting mixed in food products. Stainless steels are alloy steels exhibiting excellent corrosion resistance.
Stainless steels are roughly divided into austenite stainless steels, martensite stainless steels, and ferrite stainless steels. It is known that these stainless steels exhibit magnetic properties. Therefore, various kinds of stainless steel can be detected as metallic contaminants by using their characteristic properties.